BRAF, KRAS and PIK3CA mutations in colorectal serrated polyps and cancer: Primary or secondary genetic events in colorectal carcinogenesis?
2008

Mutations in Colorectal Polyps and Cancer

Sample size: 17 publication Evidence: moderate

Author Information

Author(s): Velho Sérgia, Moutinho Cátia, Cirnes Luís, Albuquerque Cristina, Hamelin Richard, Schmitt Fernando, Carneiro Fátima, Oliveira Carla, Seruca Raquel

Primary Institution: Institute of Molecular Pathology and Immunology, University of Porto, Portugal

Hypothesis

To determine the frequency of KRAS, BRAF and PIK3CA mutations in the process of colorectal tumourigenesis.

Conclusion

BRAF, KRAS and PIK3CA mutations occur prior to malignant transformation, indicating they are primary genetic events in colorectal carcinogenesis.

Supporting Evidence

  • KRAS, PIK3CA or BRAF mutations occur in 71% of polyps.
  • KRAS mutations occur in 35% of polyps.
  • BRAF mutations occur in 29% of cases, all classified as serrated adenoma.
  • CIMP phenotype occurred in 25% of the polyps, all mutated for BRAF.
  • The frequency of BRAF mutations in serrated polyps is similar to that in MSI CRC.

Takeaway

This study found that certain mutations in colorectal polyps happen before cancer develops, showing they are important early changes in the disease.

Methodology

Mutation analyses were performed by PCR/sequencing, and bisulfite treated DNA was used to study CIMP and MLH1 methylation.

Potential Biases

None reported.

Limitations

The study is retrospective and may not account for all variables influencing mutation frequency.

Participant Demographics

Patients included had no positive family history.

Statistical Information

P-Value

0.0191

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1186/1471-2407-8-255

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